Variscan orogeny
Encyclopedia
Paleozoic
The Paleozoic era is the earliest of three geologic eras of the Phanerozoic eon, spanning from roughly...
continental collision
Continental collision
Continental collision is a phenomenon of the plate tectonics of Earth that occurs at convergent boundaries. Continental collision is a variation on the fundamental process of subduction, whereby the subduction zone is destroyed, mountains produced, and two continents sutured together...
between Euramerica
Euramerica
Euramerica was a minor supercontinent created in the Devonian as the result of a collision between the Laurentian, Baltica, and Avalonia cratons .300 million years ago in the Late Carboniferous tropical rainforests lay over the equator of Euramerica...
(Laurussia) and Gondwana
Gondwana
In paleogeography, Gondwana , originally Gondwanaland, was the southernmost of two supercontinents that later became parts of the Pangaea supercontinent. It existed from approximately 510 to 180 million years ago . Gondwana is believed to have sutured between ca. 570 and 510 Mya,...
to form the supercontinent
Supercontinent
In geology, a supercontinent is a landmass comprising more than one continental core, or craton. The assembly of cratons and accreted terranes that form Eurasia qualifies as a supercontinent today.-History:...
of Pangaea
Pangaea
Pangaea, Pangæa, or Pangea is hypothesized as a supercontinent that existed during the Paleozoic and Mesozoic eras about 250 million years ago, before the component continents were separated into their current configuration....
.
Naming
The name, Variscan, comes from the Medieval LatinLatin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
name for the district Variscia, the home of a Germanic tribe, the Varisci
Varisci
thumb|350px|The Varisci be seen as Narister ca. 50 CE.The Varisci were a Germanic tribe, the presumed prior inhabitants of a medieval district, Provincia Variscorum, the same as the Vogtland district of Saxony in Germany...
, and was coined in 1880 by Vienna
Vienna
Vienna is the capital and largest city of the Republic of Austria and one of the nine states of Austria. Vienna is Austria's primary city, with a population of about 1.723 million , and is by far the largest city in Austria, as well as its cultural, economic, and political centre...
geologist Eduard Suess
Eduard Suess
Eduard Suess was a geologist who was an expert on the geography of the Alps. He is responsible for hypothesising two major former geographical features, the supercontinent Gondwana and the Tethys Ocean.Born in London to a Jewish Saxon merchant, when he was three his family relocated toPrague,...
. Variscite
Variscite
Variscite is a hydrated aluminium phosphate mineral |H2O]]). It is a relatively rare phosphate mineral. It is sometimes confused with turquoise; however, variscite is usually greener in color....
, a rare green mineral found in the region and first discovered in the Vogtland
Vogtland
The term Vogtland refers to a region reaching across the German free states of Bavaria, Saxony and Thuringia and into the Czech Republic . The name of the region contains a reference to the former leadership by the Vögte of Weida, Gera and Plauen, which translates approximately to advocates or lord...
district of Saxony
Saxony
The Free State of Saxony is a landlocked state of Germany, contingent with Brandenburg, Saxony Anhalt, Thuringia, Bavaria, the Czech Republic and Poland. It is the tenth-largest German state in area, with of Germany's sixteen states....
in Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
, which is in the Variscan belt, has the same etymology
Etymology
Etymology is the study of the history of words, their origins, and how their form and meaning have changed over time.For languages with a long written history, etymologists make use of texts in these languages and texts about the languages to gather knowledge about how words were used during...
. Hercynian, on the other hand, derives from the Hercynian Forest
Hercynian Forest
The Hercynian Forest was an ancient and dense forest that stretched eastward from the Rhine River across southern Germany and formed the northern boundary of that part of Europe known to writers of antiquity. The ancient sources are equivocal about how far east it extended...
. Both words were descriptive terms of strike directions observed by geologists in the field, variscan for southwest to northeast, hercynian for northwest to southeast. The variscan direction reflected the direction of ancient fold belts cropping out throughout Germany and adjacent countries and the meaning shifted from direction to the fold belt proper. One of the pioneers in research on the Variscan fold belt was the German geologist Franz Kossmat
Franz Kossmat
Franz Kossmat was an Austrian-German geologist, for twenty years the director of the Geological Survey of Saxony under both the kingdom and the subsequent German Republic....
, establishing a still valid division of the European Variscides in 1927.
The other direction, Hercynian for the direction of the Harz
Harz
The Harz is the highest mountain range in northern Germany and its rugged terrain extends across parts of Lower Saxony, Saxony-Anhalt and Thuringia. The name Harz derives from the Middle High German word Hardt or Hart , latinized as Hercynia. The legendary Brocken is the highest summit in the Harz...
Mountains in Germany, saw a similar shift in meaning. Today hercynian is often used as a synonym
Synonym
Synonyms are different words with almost identical or similar meanings. Words that are synonyms are said to be synonymous, and the state of being a synonym is called synonymy. The word comes from Ancient Greek syn and onoma . The words car and automobile are synonyms...
for variscan, being somewhat less used than the latter. In the USA it is only used for European orogenies, the contemporaneous and genetically linked mountain-building phases in the Appalachian Mountains
Appalachian Mountains
The Appalachian Mountains #Whether the stressed vowel is or ,#Whether the "ch" is pronounced as a fricative or an affricate , and#Whether the final vowel is the monophthong or the diphthong .), often called the Appalachians, are a system of mountains in eastern North America. The Appalachians...
have different names.
The regional term variscan underwent a further meaning shift since the 1960s. It now is generally used for late paleozoic fold belts and orogenetic phases having an age of approximately 380 to 280 Ma. Some publications use the term variscan for fold belts of even younger age, deviating from the meaning as a term for the North American and European orogeny related to the Gondwana-Laurasia collision.
Distribution
Portugal
Portugal , officially the Portuguese Republic is a country situated in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe, and is bordered by the Atlantic Ocean to the West and South and by Spain to the North and East. The Atlantic archipelagos of the...
and western Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
(Galicia), southwestern Ireland
Ireland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...
(i.e. Munster
Munster
Munster is one of the Provinces of Ireland situated in the south of Ireland. In Ancient Ireland, it was one of the fifths ruled by a "king of over-kings" . Following the Norman invasion of Ireland, the ancient kingdoms were shired into a number of counties for administrative and judicial purposes...
), Cornwall
Cornwall
Cornwall is a unitary authority and ceremonial county of England, within the United Kingdom. It is bordered to the north and west by the Celtic Sea, to the south by the English Channel, and to the east by the county of Devon, over the River Tamar. Cornwall has a population of , and covers an area of...
, Devon
Devon
Devon is a large county in southwestern England. The county is sometimes referred to as Devonshire, although the term is rarely used inside the county itself as the county has never been officially "shired", it often indicates a traditional or historical context.The county shares borders with...
, Pembrokeshire
Pembrokeshire
Pembrokeshire is a county in the south west of Wales. It borders Carmarthenshire to the east and Ceredigion to the north east. The county town is Haverfordwest where Pembrokeshire County Council is headquartered....
, the Gower Peninsula
Gower Peninsula
Gower or the Gower Peninsula is a peninsula in south Wales, jutting from the coast into the Bristol Channel, and administratively part of the City and County of Swansea. Locally it is known as "Gower"...
and the Vale of Glamorgan
Vale of Glamorgan
The Vale of Glamorgan is a county borough in Wales; an exceptionally rich agricultural area, it lies in the southern part of Glamorgan, South Wales...
. Its effects are present in France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
from Brittany
Brittany
Brittany is a cultural and administrative region in the north-west of France. Previously a kingdom and then a duchy, Brittany was united to the Kingdom of France in 1532 as a province. Brittany has also been referred to as Less, Lesser or Little Britain...
, below the Paris Basin
Paris Basin (geology)
The Paris Basin is one of the major geological regions of France having developed since the Triassic on a basement formed by the Variscan orogeny.-Extent:...
to the Ardennes
Ardennes
The Ardennes is a region of extensive forests, rolling hills and ridges formed within the Givetian Ardennes mountain range, primarily in Belgium and Luxembourg, but stretching into France , and geologically into the Eifel...
, the Massif Central
Massif Central
The Massif Central is an elevated region in south-central France, consisting of mountains and plateaux....
, the Vosges
Vosges
Vosges is a French department, named after the local mountain range. It contains the hometown of Joan of Arc, Domrémy.-History:The Vosges department is one of the original 83 departments of France, created on February 9, 1790 during the French Revolution. It was made of territories that had been...
and Corsica
Corsica
Corsica is an island in the Mediterranean Sea. It is located west of Italy, southeast of the French mainland, and north of the island of Sardinia....
. It shows in Sardinia
Sardinia
Sardinia is the second-largest island in the Mediterranean Sea . It is an autonomous region of Italy, and the nearest land masses are the French island of Corsica, the Italian Peninsula, Sicily, Tunisia and the Spanish Balearic Islands.The name Sardinia is from the pre-Roman noun *sard[],...
in Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
and in Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
where the Rhine Massif (Ardennes, Eifel
Eifel
The Eifel is a low mountain range in western Germany and eastern Belgium. It occupies parts of southwestern North Rhine-Westphalia, northwestern Rhineland-Palatinate and the south of the German-speaking Community of Belgium....
, Hunsrück
Hunsrück
The Hunsrück is a low mountain range in Rhineland-Palatinate, Germany. It is bounded by the river valleys of the Moselle , the Nahe , and the Rhine . The Hunsrück is continued by the Taunus mountains on the eastern side of the Rhine. In the north behind the Moselle it is continued by the Eifel...
, Taunus
Taunus
The Taunus is a low mountain range in Hesse, Germany that composes part of the Rhenish Slate Mountains. It is bounded by the river valleys of Rhine, Main and Lahn. On the opposite side of the Rhine, the mountains are continued by the Hunsrück...
and other regions on both sides of Middle Rhine
Middle Rhine
Between Bingen and Bonn, Germany, the Rhine River flows as the Middle Rhine through the Rhine Gorge, a formation created by erosion, which happened at about the same rate as an uplift in the region, leaving the river at about its original level, and the surrounding lands raised...
Valley), the Black Forest
Black Forest
The Black Forest is a wooded mountain range in Baden-Württemberg, southwestern Germany. It is bordered by the Rhine valley to the west and south. The highest peak is the Feldberg with an elevation of 1,493 metres ....
and Harz Mountains remain as testimony. In the Czech Republic
Czech Republic
The Czech Republic is a landlocked country in Central Europe. The country is bordered by Poland to the northeast, Slovakia to the east, Austria to the south, and Germany to the west and northwest....
and eastern Poland
Poland
Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...
the Bohemian Massif
Bohemian Massif
The Bohemian Massif; or Český masiv; is in the geology of Central Europe a large massif stretching over central Czech republic, eastern Germany, southern Poland and northern Austria...
is the eastern end of the Variscan belt of crustal deformation in Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
. Further Variscan developments to the southeast are partly hidden and overprinted by the alpine orogeny
Alpine orogeny
The Alpine orogeny is an orogenic phase in the Late Mesozoic and Tertiary that formed the mountain ranges of the Alpide belt...
. In the Alps
Alps
The Alps is one of the great mountain range systems of Europe, stretching from Austria and Slovenia in the east through Italy, Switzerland, Liechtenstein and Germany to France in the west....
a Variscan core is built by Mercantour, Pelvoux
Pelvoux
Pelvoux is a commune in the Hautes-Alpes department in the Provence-Alpes-Côte d'Azur region in southeastern France.Pelvoux was bidding to be the French candidate city for the 2018 Winter Olympics.-Population:-External links:* *...
, Belledonne
Belledonne
Belledonne is a mountain range in the Dauphiné Alps in southeast France. The southern end of the range forms the eastern wall of the mountains that surround the city of Grenoble....
, Montblanc
Montblanc
Montblanc may refer to:* Montblanc , a German manufacturer of writing instruments, watches and accessories* Montblanc, Hérault, a commune of the Hérault département, in France...
and Aar Massif. Dinaric, Greek
Greece
Greece , officially the Hellenic Republic , and historically Hellas or the Republic of Greece in English, is a country in southeastern Europe....
and Turkish
Turkey
Turkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...
mountain chains are the southwestern termination of the Variscan proper.
The Variscan was contemporaneous with the Acadian
Acadian orogeny
The Taconic, Acadian and Alleghenian orogenies are the three tectonic phases responsible for the formation of the present Appalachian Mountains. The Acadian orogeny is a middle Paleozoic mountain building episode dating back 325-400 million years which should not be regarded as a single event but...
and Alleghenian orogeny
Alleghenian orogeny
The Alleghenian orogeny or Appalachian orogeny is one of the geological mountain-forming events that formed the Appalachian Mountains and Allegheny Mountains. The term and spelling Alleghany orogeny was originally proposed by H.P. Woodward in 1957....
in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, forming the Ouachita
Ouachita Mountains
The Ouachita Mountains are a mountain range in west central Arkansas and southeastern Oklahoma. The range's subterranean roots may extend as far as central Texas, or beyond it to the current location of the Marathon Uplift. Along with the Ozark Mountains, the Ouachita Mountains form the U.S...
and Appalachian Mountains
Appalachian Mountains
The Appalachian Mountains #Whether the stressed vowel is or ,#Whether the "ch" is pronounced as a fricative or an affricate , and#Whether the final vowel is the monophthong or the diphthong .), often called the Appalachians, are a system of mountains in eastern North America. The Appalachians...
. Other North American areas with Variscan foldbelts include New England
New England
New England is a region in the northeastern corner of the United States consisting of the six states of Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, and Connecticut...
, Nova Scotia
Nova Scotia
Nova Scotia is one of Canada's three Maritime provinces and is the most populous province in Atlantic Canada. The name of the province is Latin for "New Scotland," but "Nova Scotia" is the recognized, English-language name of the province. The provincial capital is Halifax. Nova Scotia is the...
and Newfoundland and Labrador
Newfoundland and Labrador
Newfoundland and Labrador is the easternmost province of Canada. Situated in the country's Atlantic region, it incorporates the island of Newfoundland and mainland Labrador with a combined area of . As of April 2011, the province's estimated population is 508,400...
. The Moroccan
Morocco
Morocco , officially the Kingdom of Morocco , is a country located in North Africa. It has a population of more than 32 million and an area of 710,850 km², and also primarily administers the disputed region of the Western Sahara...
Meseta and the Anti Atlas in northwestern Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
show close relations to the Appalachian Mountains and have been the eastern part of the Appalachian orogeny before the opening of the Atlantic Ocean
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
in Jurassic
Jurassic
The Jurassic is a geologic period and system that extends from about Mya to Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...
times.
Variscan mountains in a broader sense are the Ural
Ural Mountains
The Ural Mountains , or simply the Urals, are a mountain range that runs approximately from north to south through western Russia, from the coast of the Arctic Ocean to the Ural River and northwestern Kazakhstan. Their eastern side is usually considered the natural boundary between Europe and Asia...
s, the Pamir
Pamir Mountains
The Pamir Mountains are a mountain range in Central Asia formed by the junction or knot of the Himalayas, Tian Shan, Karakoram, Kunlun, and Hindu Kush ranges. They are among the world’s highest mountains and since Victorian times they have been known as the "Roof of the World" a probable...
, the Tian Shan
Tian Shan
The Tian Shan , also spelled Tien Shan, is a large mountain system located in Central Asia. The highest peak in the Tian Shan is Victory Peak , ....
and other Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
n foldbelts.
Formation
The Variscan orogeny involved a complicated heterogeneous assembly of different microplates and heterochronous collisions, making the exact reconstruction of the plate tectonic processes difficult. Plate convergence that caused the Caledonian orogenyCaledonian orogeny
The Caledonian orogeny is a mountain building era recorded in the northern parts of the British Isles, the Scandinavian Mountains, Svalbard, eastern Greenland and parts of north-central Europe. The Caledonian orogeny encompasses events that occurred from the Ordovician to Early Devonian, roughly...
in the Silurian
Silurian
The Silurian is a geologic period and system that extends from the end of the Ordovician Period, about 443.7 ± 1.5 Mya , to the beginning of the Devonian Period, about 416.0 ± 2.8 Mya . As with other geologic periods, the rock beds that define the period's start and end are well identified, but the...
continued to form the Variscan orogeny in the succeeding Devonian
Devonian
The Devonian is a geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 416.0 ± 2.8 Mya , to the beginning of the Carboniferous Period, about 359.2 ± 2.5 Mya...
and Carboniferous
Carboniferous
The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Mya , to the beginning of the Permian Period, about 299.0 ± 0.8 Mya . The name is derived from the Latin word for coal, carbo. Carboniferous means "coal-bearing"...
Periods. Both orogenies resulted in the assembly of a super-continent, Pangaea
Pangaea
Pangaea, Pangæa, or Pangea is hypothesized as a supercontinent that existed during the Paleozoic and Mesozoic eras about 250 million years ago, before the component continents were separated into their current configuration....
, which was essentially complete by the end of the Carboniferous.
In the Ordovician
Ordovician
The Ordovician is a geologic period and system, the second of six of the Paleozoic Era, and covers the time between 488.3±1.7 to 443.7±1.5 million years ago . It follows the Cambrian Period and is followed by the Silurian Period...
Period, a land mass, which has been named Gondwana (present day South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
, Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
, Antarctica and Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
), straddled the space between the South Pole
South Pole
The South Pole, also known as the Geographic South Pole or Terrestrial South Pole, is one of the two points where the Earth's axis of rotation intersects its surface. It is the southernmost point on the surface of the Earth and lies on the opposite side of the Earth from the North Pole...
and the Equator
Equator
An equator is the intersection of a sphere's surface with the plane perpendicular to the sphere's axis of rotation and containing the sphere's center of mass....
on one side of the globe. Off to the west were three other masses: Laurentia
Laurentia
Laurentia is a large area of continental craton, which forms the ancient geological core of the North American continent...
, Siberia
Siberia
Siberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...
and Baltica
Baltica
Baltica is a name applied by geologists to a late-Proterozoic, early-Palaeozoic continent that now includes the East European craton of northwestern Eurasia. Baltica was created as an entity not earlier than 1.8 billion years ago. Before this time, the three segments/continents that now comprise...
, located as if on the vertices of a triangle. To the south of them was a large archipelago, the terrane
Terrane
A terrane in geology is short-hand term for a tectonostratigraphic terrane, which is a fragment of crustal material formed on, or broken off from, one tectonic plate and accreted or "sutured" to crust lying on another plate...
Avalonia
Avalonia
Avalonia was a microcontinent in the Paleozoic era. Crustal fragments of this former microcontinent underlie south-west Great Britain, and the eastern coast of North America. It is the source of many of the older rocks of Western Europe, Atlantic Canada, and parts of the coastal United States...
, rifted off the north Gondwana margin in early Ordovician.
By the end of the Silurian
Silurian
The Silurian is a geologic period and system that extends from the end of the Ordovician Period, about 443.7 ± 1.5 Mya , to the beginning of the Devonian Period, about 416.0 ± 2.8 Mya . As with other geologic periods, the rock beds that define the period's start and end are well identified, but the...
and in Early Devonian times, Baltica and Laurentia drifted towards each other, closing the Iapetus Ocean
Iapetus Ocean
The Iapetus Ocean was an ocean that existed in the Neoproterozoic and Paleozoic eras of the geologic timescale . The Iapetus Ocean was situated in the southern hemisphere, between the paleocontinents of Laurentia, Baltica and Avalonia...
between them. They collided in the Caledonian orogeny
Caledonian orogeny
The Caledonian orogeny is a mountain building era recorded in the northern parts of the British Isles, the Scandinavian Mountains, Svalbard, eastern Greenland and parts of north-central Europe. The Caledonian orogeny encompasses events that occurred from the Ordovician to Early Devonian, roughly...
and formed the Caledonide mountains of North America, Greenland
Greenland
Greenland is an autonomous country within the Kingdom of Denmark, located between the Arctic and Atlantic Oceans, east of the Canadian Arctic Archipelago. Though physiographically a part of the continent of North America, Greenland has been politically and culturally associated with Europe for...
, the British Isles and Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...
. Seafloor spreading
Seafloor spreading
Seafloor spreading is a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge. Seafloor spreading helps explain continental drift in the theory of plate tectonics....
to the south of Avalonia pushed the latter into north Laurentia and thrust up the northern Appalachian Mountains in the acadian phase
Acadian orogeny
The Taconic, Acadian and Alleghenian orogenies are the three tectonic phases responsible for the formation of the present Appalachian Mountains. The Acadian orogeny is a middle Paleozoic mountain building episode dating back 325-400 million years which should not be regarded as a single event but...
of the Caledonian orogeny. Contemporaneously the Tornquist Sea
Tornquist Sea
The Tornquist Sea between Avalonia and Baltica probably formed at the same time as the Iapetus Ocean. Gondwana, including Avalonia until Early Ordovician, was separate from Baltica throughout the Cambrian...
between Avalonia and Baltica was entirely closed. Thus Avalonia formed the southern coast of the new continent Euramerica
Euramerica
Euramerica was a minor supercontinent created in the Devonian as the result of a collision between the Laurentian, Baltica, and Avalonia cratons .300 million years ago in the Late Carboniferous tropical rainforests lay over the equator of Euramerica...
(Laurussia, the Old Red Sandstone
Old Red Sandstone
The Old Red Sandstone is a British rock formation of considerable importance to early paleontology. For convenience the short version of the term, 'ORS' is often used in literature on the subject.-Sedimentology:...
continent
Continent
A continent is one of several very large landmasses on Earth. They are generally identified by convention rather than any strict criteria, with seven regions commonly regarded as continents—they are : Asia, Africa, North America, South America, Antarctica, Europe, and Australia.Plate tectonics is...
in present day North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
, British Isles
British Isles
The British Isles are a group of islands off the northwest coast of continental Europe that include the islands of Great Britain and Ireland and over six thousand smaller isles. There are two sovereign states located on the islands: the United Kingdom of Great Britain and Northern Ireland and...
, northern Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
, Scandinavia
Scandinavia
Scandinavia is a cultural, historical and ethno-linguistic region in northern Europe that includes the three kingdoms of Denmark, Norway and Sweden, characterized by their common ethno-cultural heritage and language. Modern Norway and Sweden proper are situated on the Scandinavian Peninsula,...
and western Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
). In late Devonian and in the Carboniferous the archipelago Armorica
Armorican terrane
The Armorican terrane, Armorican terrane assemblage, or simply Armorica, refers to a microcontinent or group of continental fragments that rifted away from Gondwana towards the end of the Silurian and collided with Laurussia towards the end of the Carboniferous during the Variscan orogeny...
of southern Europe, which had rifted off Gondwana after Avalonia later in the Ordovician, was pushed into Avalonia, creating a second range, the North American/European Variscan, to the east of the Caledonide/Appalachian. The collision of Gondwana proper with Laurussia followed in the early Carboniferous, when the Variscan belt was already in place and actively developing.
By the end of the Carboniferous, Gondwana had united with Laurussia on its western end through northern South America and northwestern Africa. Siberia was approaching from the northeast, separated from Laurussia only by shallow waters. Collision with Siberia produced the Ural Mountains
Ural Mountains
The Ural Mountains , or simply the Urals, are a mountain range that runs approximately from north to south through western Russia, from the coast of the Arctic Ocean to the Ural River and northwestern Kazakhstan. Their eastern side is usually considered the natural boundary between Europe and Asia...
in the latest Paleozoic and completed the formation of Pangea. Eastern Laurussia was still divided from Gondwana by the Paleotethys Ocean.
In the Triassic
Triassic
The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...
Period of the Mesozoic
Mesozoic
The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...
Era, animals could move without oceanic impediment from Siberia over the North Pole to Antarctica over the South Pole. In the Mesozoic
Mesozoic
The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...
Era, the opening of the Atlantic split Pangea. As a consequence, the Variscan Belt around the then periphery of Baltica ended up many hundreds of miles from the Appalachians.